There is a vast range of 3D modellers out there, as for the decent-ness, well that one depends entirely on what you prefer, I'll offer a recommended list of applications that are good for game integration and the direct X format.
Blender - Free - Some find the interface difficult, others just dislike it
Milkshape 3D - $25 - I would use this with a free program call Wings 3D, I don't like MS3D's 3D modelling part, but wings 3D works there and Milkshape can be good for animation and exportation, this is what I recommend for newbies.
GameSpace - Over $100 - I didn't like it's big brother's way of working, but a lot of people like this application.
Softimage|XSI Foundation - $500/£300 - The first professional package, in my opinion the ultimate value for a 3D program for students, hobbiests and indies, you can produce amazing result when skilled with this, this is my next buy.
Softimage|XSI Essentials - £2000 - Same as above but with more features
3D Studio Max - $3000 - I think this is overrated, it is a good program, however, it is $3000 and isn't the best value, it's powerful, it has more features that Softimage|XSI Foundation and Essentials, but XSI has more value for money in my opinion and you can pretty much get the same results, except XSI is becoming more preferred for game content, for one thing it's animation tools are becoming loved so much that there's a plugin for 3DS Max so you can use them there, heck Happy Feet was animated in Softimage and Rendered in Maya.
Softimage|XSI Advanced - $7000 - The ultimate version of Softimage|XSI packed with all of it's features
Maya Unlimited $8000 - Quite commonly used in the film business, but is good for games, I don't know any of the game titles, but it is a loved program.
I know there was no point posting the expensive lot, but its good to know what's out there that is used or recommended for the game industry and can export .x because if you go serious you may find yourself choosing.
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